command

Only shell builtin commands or commands found
by searching the PATH are executed. If there is a shell function
named ls, running `command ls' within the function
will execute the external command ls instead of calling the function
recursively.

The `-p' option means to use a default value for $PATH
that is guaranteed to find all of the standard utilities. The return status
in this case is 127 if command cannot be found or an error occurred,
and the exit status of command otherwise.

If either the `-V' or `-v' option is supplied, a description
of command is printed. The `-v' option causes a single
word indicating the command or file name used to invoke command to
be displayed; the `-V' option produces a more verbose description.
In this case, the return status is zero if command is found, and
non-zero if not.

"If you're not failing every now and again, it's a sign you're not doing anything very innovative" - Woody Allen
Related:

builtin - Run a shell builtincrontab - Schedule a command to run at a later timechroot - Run a command with a different root directoryexec - Execute a commandif - Conditionally perform a commandnohup - Run a command immune to hangups.source - Run commands from a file su - Run a command with substitute user and group idtype - Describe a command watch - Execute/display a program periodically